| 摘要 |
PURPOSE:To exactly adjust the focus to an object to be photographed even if the object to be photographed does not exist in the center part of a photographing range by forming a shape of a light emission spot so that width in the horizontal direction becomes larger than that in the vertical direction. CONSTITUTION:In an elliptical light emission spot forming means, a columnar lens 1b, and a projection lens consisting of a convex lens 1a are placed in front of a light emitting element 2. According to this projection lens system, although a shape is different to some extent in accordance with a distance, a spot in which width in the horizontal direction is larger than width in the vertical direction is obtained. In the case when the horizontal width is enlarged by a circular spot, the focusing accuracy is deteriorated, but since the spot width in the vertical direction is small as in this system, even if the width in the horizontal direction is enlarged, the focusing accuracy is not deteriorated, and the focus is adjusted exactly to an object to be photographed which does not exist in the center part, extending over a wide photographing range. |
